DESCRIPTION: (Investigator's abstract): Results using an optical approach to study patterns of cortical organization suggest that response properties in addition to ocular dominance and orientation may be organized laterally (tangentially). Funds are requested in the present proposal to continue this analysis using micro-electrodes in conjunction with optical imaging to determine what these properties are and how they relate to known organizations of ocular dominance and orientation. Each of the proposed experiments will begin with optical techniques that map ocular dominance and orientation and reveal borders where orientation changes abruptly (fractures). Selected 0.5-1.0 mm segments of orientation fractures, iso-orientation bands, and ocular dominance bands will then be examined in greater detail with electrode penetrations. Cells that are isolated from the upper layers will then be tested for response properties that might be organized laterally. These experiments are designed to increase our understanding of visual information processing and associated structure-function relationships in the upper layers of monkey striate cortex.